body{
    background: #fff;
}
header{
    margin-top: 50px;
    height: 33px;
    border: 1px solid #c9c8c8;
    border-left: none;
    border-right:none;
}
header nav{
    width: 1005px;
    margin: 0 auto;
}
/* 子绝父相 */
header nav a{
    float: left;
    width: 199px;
    height:33px;
    line-height: 33px;
    text-align: center;
    color: #333;
    font-size: 13px;
    border-left: 1px solid #c9c8c8;
    border-right: 1px solid #c9c8c8;
    position: relative;
}
nav a img{
    position: absolute;
    left:50%;
    transform: translateX(-50%);
    top: 35px;
}
header nav a:first-child{
    border-left: none;
}
header nav a:last-child{
    border-right: none;
}